Defect Healing and Charge Transfer-Mediated Valley Polarization in MoS<sub>2</sub>/MoSe<sub>2</sub>/MoS<sub>2</sub> Trilayer van der Waals Heterostructures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28603999.
- Also identified by DOI 10.1021/acs.nanolett.7b00904.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Monolayer transition metal dichalcogenides (TMDCs) grown by chemical vapor deposition (CVD) are plagued by a significantly lower optical quality compared to exfoliated TMDCs. In this work, we show that the optical quality of CVD-grown MoSe<sub>2</sub> is completely recovered if the material is sandwiched in MoS<sub>2</sub>/MoSe<sub>2</sub>/MoS<sub>2</sub> trilayer van der Waals heterostructures. We show by means of density functional theory that this remarkable and unexpected result is due to defect healing: S atoms of the more reactive MoS<sub>2</sub> layers are donated to heal Se vacancy defects in the middle MoSe<sub>2</sub> layer. In addition, the trilayer structure exhibits a considerable charge-transfer mediated valley polarization of MoSe<sub>2</sub> without the need for resonant excitation. Our fabrication approach, relying solely on simple flake transfer technique, paves the way for the scalable production of large-area TMDC materials with excellent optical quality.